CELLULOSE NANOCRYSTALS AND GRAPHENE REINFORCED POLYMERIC BIONANOCOMPOSITES

Abstract

Bionanocomposites signify an emerging group of nanostructured hybrid materials. They are developed by the combination of natural polymers and inorganic solids and show at least one dimension on the nanometer scale. Similar to conventional nanocomposites, which involve synthetic polymers, these biohybrid materials also display enhanced functional and structural properties of great interest for different applications. The properties inherent to the biopolymers, that is, biocompatibility and biodegradability, open new prospects for these hybrid materials in an environmentally friendly materials (green nanocomposites). Research on bionanocomposites can be considered as a new interdisciplinary field closely related to significant topics such as bioinspired materials and biomimetic systems. The upcoming development of novel bionanocomposites introducing multifunctionality represents a promising research topic that takes advantage of synergistic assembling of biopolymers with inorganic nanometer-sized solids. Thus, the current thesis focusses on development of cellulose nanocrystals (CNC) and graphene based polymeric bionanocomposites to address multifunctionality in novel nanocomposites. First part of the study focusses on exploration of simplistic in situ synthesis method for CNC and rGO incorporated in PLA matrix using solution casting method. The percentage of CNC and rGO into PLA matrix was optimized and synthesis was validated by various characterization methods including Transmission Electron Microscopy (TEM), Field-Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The hydrophilicity of film was measured by wettability analysis. The optimized nanocomposite with CNC and rGO showed increased tensile strength upto 23% with an increase in elongation behavior indicating ductile behavior of nanocomposite compared to pristine PLA. The PLA/CNC/rGO nanocomposite displayed antibacterial efficacy against both Gram positive Staphylococcus aureus (S.aureus) and Gram negative Escherichia coli. (E.coli) bacterial strains. Further studies also showed that the PLA/CNC/rGO nanocomposite was non-toxic to NIH-3T3 fibroblast cell line. Therefore, the as fabricated nanocomposite film possesses considerable potential in biomedical as well as in food packaging applications.